Fluent, the game is difficult at first because people don't know the mechanics. There are lots of things from the start that allow an experienced player to totally smash through monsters at any level with (almost) any equipment. A few examples of things you CAN'T do in DS are:
*spam attacks without planning - every swing is a commitment, if you miss, you are open for a counterattack
*rush in carelessly - if it's a new enemy - raise your shield; you need to know the moves of enemies so you know when you can safely attack without taking damage yourself
*heal up during the fight without earning it first - in Dark Souls, the time it takes to drink a potion is roughly equivalent to the time it would take you to make a swing. That means that the only time you are safe to heal is when your enemy is open for attacks - you can't heal at any time you like, you need to create an opening first.
Those are some basic examples of lessons DS tries to teach you. There are many other things that you need to know in order to defeat the game. I feel that above everything else, Dark Souls is a learning experience. If there were an easy mode, you wouldn't need to know about parrying, blocking, weapon speed or the moves of your enemies; you would simply swing your weapon, do more damage than is done to you, and defeat them. If you take the learning away from a game that is all about that, you are left with nothing. That is what Dark Souls would be with an easy mode - nobody would learn without the need to. If the game is hard, and you have an easy way out (easy mode), you are likely to just choose that and never truly learn what DS is about.
What I do agree is that the game should explain some of its mechanics better, and force you to do each of the basic moves at least once so you know your arsenal better.